This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to Patent Application Serial No. 0100252-6 filed in Sweden on Jan. 30, 2001, the entire content of which is hereby incorporated by reference.
The present invention relates to a tool holder for cutting inserts for chip removing machining, the tool holder comprising a head, as well as a seat having side surfaces which engage side edges of the clamped-in cutting insert. One of the side surfaces of the seat is flexible.
In a leaflet from ISCAR, entitled xe2x80x9cISCAR""s New Clamping System for Profiling Toolsxe2x80x9d conventional prior art is shown, which is illustrated herein in FIGS. 10 and 11, as well as a further development of prior art, which is illustrated in FIG. 12 herein.
As is seen in FIGS. 10 and 11, in the conventional prior art there is disclosed a three-point abutment. In case the cutting insert S is exposed to a force Fc1 acting from the right, see FIG. 10, the cutting insert S will abut at two points CP1 and CP2 against the stiffer side surface 100 of a holder 102 and at one point CP3 against a more resilient side surface 104. This is illustrated in FIG. 10 by an angle xcex41 formed between the cutting insert S and the more resilient side surface.
If the force Fc2 acting on the cutting insert S comes from the left, see FIG. 11, the cutting insert S will abut against the stiffer side surface at one point CP1 and at two points CP3 and CP4 against the more resilient side surface. This is illustrated in FIG. 11 by an angle xcex42 formed between the cutting insert S and the stiffer side surface.
Clamping of the cutting insert S is normally effected with a so-called rocking pin 106, possibly in combination with a top clamp. This has turned out to be insufficient in a number of applications, i.e., the position of the cutting insert is not anchored in the holder to a sufficiently high degree of accuracy. This is particularly valid for this elongated type of cutting insert where large movements of the insert occurs if the insert is exposed to varying loads from differing directions, which is the case in, for instance, copy turning.
As can be seen in the prior art illustrated in FIG. 12, the insert seat is provided with a self-adjusting wedge W which abuts against a side surface of the cutting insert, the wedge being movable and self-adjusting to the cutting insert so that a four-point abutment CP1, CP2, CP3, CP4 is obtained. Since the self-adjusting wedge is movable, the fixation of the cutting insert in the insert seat will also in this case be inadequate for certain applications.
A turning tool having a replaceable indexable insert is previously known from DE 37 14 055. In certain of the embodiments, see FIGS. 4, 4a and 5, of a timing tool according to DE 37 14 055, a flat wedge abutting against the indexable insert is provided with opposite slots, the open ends of which break through the longitudinal side edges of the flat wedge. The flat wedge abuts against the indexable insert with two contact points. A disadvantage of this known turning tool is that if the side surface of the insert seat that is integrated with the proper turning tool is damaged or becomes worn out, the entire turning tool has to be replaced, which is disadvantageous from the point of view of cost. As for the forces being transferred from the indexable insert to the two contact points of the flat wedge, said forces will pass past the open ends of the slots, which means that the slots are compressed in the area of the open ends thereof. Thus, the flat wedge will give way and thereby not give any active support to the cutting insert when the same tries to turn because of the external forces affecting the insert tip.
A primary aim of the present invention is to provide a tool holder of the above-mentioned kind, where an exceptionally accurate clamping of the cutting insert in the insert seat is obtained, this notwithstanding that the cutting insert is exposed to varying sizes and/or directions of loading during, for instance, copy turning. The consequence of this is increased dimensional precision through the use of the tool holder.
Yet another aim of the present invention is that the cutting insert is to be anchored in the insert seat by means of a so-called four-point abutment.
Another aim of the present invention is that the insert seat should align automatically to the cutting insert when the same is anchored in the appurtenant insert seat thereof.
The present invention relates to a tool holder for holding a cutting insert for chip removing machining. The holder comprises a head and a support surface disposed on the head and adapted to support a cutting insert. A plate-shaped member is removably secured on the head and includes two fingers forming respective side surfaces disposed on respective sides of the support surface. The side surfaces face one another and extend generally perpendicularly to the support surface. Each of the side surfaces includes a recess disposed intermediate opposite ends thereof, wherein each side surface defines spaced apart contact areas. One of the fingers includes a through-slot spaced from the respective side surface and extending generally therealong to render that support surface flexible.
Preferably, a passage extends between an intermediate portion of the flexible side surface and an intermediate portion of the through-slot.
Preferably, the plate-shaped member includes a first serrated surface seated on a second serrated surface of the head to define a serrated connection between the plate-shaped member and the head. The serrated connection is omitted at one of the fingers.